Commit a5e16079 authored by Yu Kuai's avatar Yu Kuai Committed by openeuler-sync-bot
Browse files

md/raid1-10: submit write io directly if bitmap is not enabled 

mainline inclusion
from mainline-v6.5-rc1
commit 7db922ba
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I8UKFJ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7db922bae3abdf0a1db81ef7228cc0b996a0c1e3



----------------------------------------

Commit 6cce3b23 ("[PATCH] md: write intent bitmap support for raid10")
add bitmap support, and it changed that write io is submitted through
daemon thread because bitmap need to be updated before write io. And
later, plug is used to fix performance regression because all the write io
will go to demon thread, which means io can't be issued concurrently.

However, if bitmap is not enabled, the write io should not go to daemon
thread in the first place, and plug is not needed as well.

Fixes: 6cce3b23 ("[PATCH] md: write intent bitmap support for raid10")
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-5-yukuai1@huaweicloud.com


Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
(cherry picked from commit 70603cce)
parent 415d86ef

drivers/md/md-bitmap.c

+1 −3
Original line number Diff line number Diff line
@@ -1001,7 +1001,6 @@ static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block) 
	return set;

}





/* this gets called when the md device is ready to unplug its underlying

 * (slave) device queues -- before we let any writes go down, we need to

 * sync the dirty pages of the bitmap file to disk */
@@ -1011,8 +1010,7 @@ void md_bitmap_unplug(struct bitmap *bitmap) 
	int dirty, need_write;

	int writing = 0;



	if (!bitmap || !bitmap->storage.filemap ||

	    test_bit(BITMAP_STALE, &bitmap->flags))

	if (!md_bitmap_enabled(bitmap))

		return;



	/* look at each page to see if there are any set bits that need to be

drivers/md/md-bitmap.h

+7 −0
Original line number Diff line number Diff line
@@ -273,6 +273,13 @@ int md_bitmap_copy_from_slot(struct mddev *mddev, int slot, 
			     sector_t *lo, sector_t *hi, bool clear_bits);

void md_bitmap_free(struct bitmap *bitmap);

void md_bitmap_wait_behind_writes(struct mddev *mddev);



static inline bool md_bitmap_enabled(struct bitmap *bitmap)

{

	return bitmap && bitmap->storage.filemap &&

	       !test_bit(BITMAP_STALE, &bitmap->flags);

}



#endif



#endif

drivers/md/raid1-10.c

+11 −2
Original line number Diff line number Diff line
@@ -131,9 +131,18 @@ static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio, 
				      blk_plug_cb_fn unplug)

{

	struct raid1_plug_cb *plug = NULL;

	struct blk_plug_cb *cb = blk_check_plugged(unplug, mddev,

						   sizeof(*plug));

	struct blk_plug_cb *cb;



	/*

	 * If bitmap is not enabled, it's safe to submit the io directly, and

	 * this can get optimal performance.

	 */

	if (!md_bitmap_enabled(mddev->bitmap)) {

		raid1_submit_write(bio);

		return true;

	}



	cb = blk_check_plugged(unplug, mddev, sizeof(*plug));

	if (!cb)

		return false;